The Curbsiders Internal Medicine Podcast

Episode #471: Iron Deficiency Anemia with Dr. Tom DeLoughery

Date: February 17, 2025
Host: Dr. Matthew Frank Watto, Dr. Paul Nelson Williams, Dr. Sai Achi
Guest: Dr. Tom DeLoughery, Hematologist, Oregon Health & Science University

Episode Overview

This episode dives deep into the diagnosis and management of iron deficiency anemia, a condition common in internal medicine but rife with diagnostic and therapeutic nuances. Returning guest and hematology educator Dr. Tom DeLoughery brings a blend of evidence-based pearls and practical insights, exploring everything from interpreting CBCs to choosing and dosing oral and IV iron. Listeners will gain updated guidance for recognizing true iron deficiency, setting appropriate ferritin cutoffs, optimizing iron replacement strategies (including patient counseling and dietary myths), and knowing when to escalate care. The discussion is engaging, occasionally irreverent, and packed with clinical "aha!" moments for learners at all levels.

Key Discussion Points & Insights

1. Approaching Anemia: Diagnostic Framework

[09:36]

Initial approach: Assess for bleeding, prior anemia, family history, and GI/celiac symptoms.
Begin with a basic CBC review. Use a focused workup guided by MCV and clinical clues.

“When I see somebody’s anemic and labs come back anemic...have you been bleeding?...stomach upset, diarrhea—trying to tease out celiac disease.”
— Dr. DeLoughery [09:36]

Dr. DeLoughery’s Quick CBC Review

[13:42]

Focus on hemoglobin, MCV, and red cell count.
Avoid over-interpreting indices like RDW or MCHC, as they're rarely helpful diagnostically.

"For a CBC, I’m fairly limited...if they adopted my view on CBCs, we’d save so many trees and paper.”
— Dr. DeLoughery [14:27]

Parlor Trick: Distinguishing Thalassemia vs Iron Deficiency

[15:49]

MCV ÷ RBC (in millions):
- <13: Thalassemia likely
- >13: Iron deficiency more likely
“In thalassemia you make a lot of little red cells. In iron deficiency, you don’t make a lot of little red cells.”
— [15:49]

2. Iron Studies: What Really Matters

[19:21 & 21:04]

Ferritin is the single most reliable test for iron deficiency.
Transferrin saturation and TIBC are less useful, especially in inflammation or elderly patients—can be misleading.

“The one test that is most predictive is the serum ferritin. So I just tend to go with that.”
— Dr. DeLoughery [20:49]

3. Ferritin Cutoffs—A Paradigm Shift

[21:04]

Classic lower limits (e.g., 15–30 ng/mL) are too low; they reflect iron-deficient reference populations.
Modern cutoff:
- Under 30 is highly sensitive/specific for negative iron stores
- Under 50 is a better cutoff for symptomatic/fatigued patients or for normalization of absorption.
Higher cutoffs (e.g., 75–100+) may be needed for conditions like restless legs syndrome and alopecia.

“We need to move away from population-based data to more physiologic data...For a healthy person, probably 30...What's interesting though is there's two studies that show...for feeling better is 50 with oral iron.”
— Dr. DeLoughery [21:04]

Inflammation Pitfall

Ferritin is an acute phase reactant but in pure iron deficiency, rarely rises above 100—even in inflamed states.

“If somebody’s ferritin is 600, they are not iron deficient, because you need iron to make the ferritin protein.”
— [23:05]

Clinical Pearl

[27:23]

Fatigue/alopecia/restless legs may require ferritin >75–100; “...give [such patients] iron, it stops falling out again. It didn’t work for me.”
— Dr. DeLoughery

4. Counseling Patients—Diet Myths & Realities

[28:17–32:26]

Heme iron (animal sources) is best absorbed; plant (non-heme) iron, e.g., from spinach, is poorly absorbed and can even chelate iron due to oxalates.
Eating steak isn’t enough for those already iron-deficient.

“If somebody’s iron deficient, just eating steak three times a day is not going to get them back up...they’re going to need supplementation.”
— [32:15]

5. Oral Iron Supplementation—Modern Best Practices

[33:27]

Once daily dosing (not TID)! Higher frequency increases hepcidin, blocking absorption.
With or without food? With food is fine for patient comfort and actual intake; “meaty” foods double iron absorption.
Vitamin C with iron helps (especially to counteract dietary inhibitors).
Avoid tea/coffee within an hour of iron—tannins drastically reduce absorption, not caffeine.
For adherence, daily or three-times-weekly (e.g., M/W/F) is fine.

“Once a day at most...People say take it on empty stomach - theoretically absorption may be better. People really don't like things on empty stomach.”
— [33:27]

“I’ve always wanted to actually make an iron pill wrapped in bacon...call it iron in a blanket.”
— [28:17]

Every Other Day Dosing Controversy

[37:09]

Every other day can improve absorption, but total iron repletion at 90 days is similar or slightly slower than daily dosing.
GI side effects less common with every other day; overall, patient preference/tolerance guides choice.

6. IV Iron—When and How

Indications:

Failure/intolerance to oral iron (no need to try endless oral formulations)
High pretest probability of non-absorption (bariatric surgery, IBD, ongoing bleeding, severe deficiency)
[48:10–49:19]

Dosing/Prep Selection:
[50:36–54:30]

Multi-dose iron salts (iron sucrose, ferrous gluconate): practical downfalls, adherence issues.
Preferred:
- Low Molecular Weight Iron Dextran: Single 1000mg dose, safe & well-tolerated.
- Ferumoxytol: 510mg x2 a week apart (off-label, single 1020mg dose works but not always insurance-covered).
- Ferric Derisomaltose: Fast, single dose, but more expensive.
Ferric Carboxymaltose: Watch for significant hypophosphatemia; avoid unless necessary.

“Single dose iron...One stop shopping, and boom, the patient’s repleted.”
— Dr. DeLoughery [51:28]

IV Iron Safety, Side Effects, and Counseling

[56:48–57:42]

Infusion reactions (not true allergy) occur 1–4% of the time and are minor; anaphylaxis is exceedingly rare.
No good evidence that IV iron increases infection in most settings.

“True, severe anaphylaxis, very, very rare – like 1 in 15,000. And so it’s a very safe product to give.”
— [57:11]

7. Population Pearls

Premenopausal women: Take a menstrual history—heavy periods underrecognized as a cause; GI workup unnecessary unless over 40 or with risk factors.

“You gotta take a menstrual history...that can really pay off.”
— [44:35]
Celiac workup: Always in men, and low threshold in women with unexplained anemia or GI symptoms.
Unexplained iron deficiency: 20–30% of cases, extensive workup remains “negative”—reassure, monitor, treat supportively.

8. Monitoring & Follow-Up

[58:41–60:46]

For oral iron: Check CBC at 2 weeks, expect 1g/dL rise in hemoglobin; monitor ferritin at 3 months, aiming >50 (or higher with ongoing symptoms).
For IV iron: Check ferritin at 4–6 weeks (earlier = artificially high). Repeat as needed; expect ferritins in 200–300s after repletion, not a toxicity sign.

Notable Quotes (/ Memorable Moments)

On public speaking:

“If you study, you actually know more than anybody else in the audience about it because it's fresh on your mind.”
— Dr. DeLoughery [05:53]
On heavy periods:

“Average American woman needs 2.4 to 3.54 mg of iron a day to keep up with menstrual losses...and average diet intake is 1.8 mg!”
— [44:35]
On iron-rich foods:

“Moose actually has the highest amount of iron in it.”
— [29:54]
On why spinach is not the answer:

“Spinach is a not that great a source of iron, and it hurts patients...it actually chelates iron.”
— [32:26]
On surprising ferritin cutoffs:

“Ferritin of 13 is not normal in any situation. Maybe for other forms of life, but not in humans.”
— [68:59]

Timestamps for Major Segments

[09:36] Initial anemia assessment, case intro, CBC review
[13:42] Systematic CBC reading, thalassemia/iron deficiency trick
[19:21] Iron studies: Ferritin vs. TIBC/Transferrin saturation
[21:04] Setting ferritin cutoffs & the pitfalls of population reference ranges
[27:23] Higher ferritin targets for restless legs/alopecia
[28:17] Dietary pearls & myths (heme vs. non-heme iron, spinach myth)
[33:27] Oral iron dosing, hepcidin, food/vitamin C/tea tips
[37:09] Once daily vs. every other day iron dosing controversy
[48:10] When to move to IV iron
[50:36] IV iron products—dosing, pros/cons, hypophosphatemia warning
[56:48] Safety of IV iron, reactions, counseling on side effects
[58:41] Monitoring response, CBC/ferritin follow-up
[68:59] Take-home points

Take Home Points (Dr. Tom DeLoughery) [68:59]

Iron deficiency is common—define it physiologically, not statistically. For ferritin, use 30 (minimum) or 50 (symptomatic) as your cutoff, not lab “normals”.
In women, take a menstrual history. It’s key and too often missed.
Prescribe iron once a day at most; give with food/meat for tolerance and absorption.
Don’t hesitate to move to IV iron—don’t “torture” patients with endless pill trials.
Ferritin in the 200–300s post IV iron is okay—don’t sweat it.
IV iron is safe—infusion reactions are rare and usually minor.

“Iron deficiency is really common… and we need to have a physiologic approach to lab values. 30, 50 ferritin cutoff, that’s what you got to keep in your mind. Ferritin of 13 is not normal in any situation… Iron once a day at most… and don’t be afraid to use IV iron.”
— Dr. DeLoughery [68:59]

For further learning, see Bethany Samuelson Bannow’s episode on high menstrual bleeding and Dr. Michael Auerbach on IV iron (referenced by the hosts).

Summary prepared for those seeking a comprehensive, practical update on iron deficiency anemia—and a few laughs.

The Curbsiders Internal Medicine Podcast

Episode #471: Iron Deficiency Anemia with Dr. Tom DeLoughery

Date: February 17, 2025
Host: Dr. Matthew Frank Watto, Dr. Paul Nelson Williams, Dr. Sai Achi
Guest: Dr. Tom DeLoughery, Hematologist, Oregon Health & Science University

Episode Overview

Key Discussion Points & Insights

1. Approaching Anemia: Diagnostic Framework

[09:36]

Initial approach: Assess for bleeding, prior anemia, family history, and GI/celiac symptoms.
Begin with a basic CBC review. Use a focused workup guided by MCV and clinical clues.

“When I see somebody’s anemic and labs come back anemic...have you been bleeding?...stomach upset, diarrhea—trying to tease out celiac disease.”
— Dr. DeLoughery [09:36]

Dr. DeLoughery’s Quick CBC Review

[13:42]

Focus on hemoglobin, MCV, and red cell count.
Avoid over-interpreting indices like RDW or MCHC, as they're rarely helpful diagnostically.

"For a CBC, I’m fairly limited...if they adopted my view on CBCs, we’d save so many trees and paper.”
— Dr. DeLoughery [14:27]

Parlor Trick: Distinguishing Thalassemia vs Iron Deficiency

[15:49]

MCV ÷ RBC (in millions):
- <13: Thalassemia likely
- >13: Iron deficiency more likely
“In thalassemia you make a lot of little red cells. In iron deficiency, you don’t make a lot of little red cells.”
— [15:49]

2. Iron Studies: What Really Matters

[19:21 & 21:04]

Ferritin is the single most reliable test for iron deficiency.
Transferrin saturation and TIBC are less useful, especially in inflammation or elderly patients—can be misleading.

“The one test that is most predictive is the serum ferritin. So I just tend to go with that.”
— Dr. DeLoughery [20:49]

3. Ferritin Cutoffs—A Paradigm Shift

[21:04]

Classic lower limits (e.g., 15–30 ng/mL) are too low; they reflect iron-deficient reference populations.
Modern cutoff:
- Under 30 is highly sensitive/specific for negative iron stores
- Under 50 is a better cutoff for symptomatic/fatigued patients or for normalization of absorption.
Higher cutoffs (e.g., 75–100+) may be needed for conditions like restless legs syndrome and alopecia.

“We need to move away from population-based data to more physiologic data...For a healthy person, probably 30...What's interesting though is there's two studies that show...for feeling better is 50 with oral iron.”
— Dr. DeLoughery [21:04]

Inflammation Pitfall

Ferritin is an acute phase reactant but in pure iron deficiency, rarely rises above 100—even in inflamed states.

“If somebody’s ferritin is 600, they are not iron deficient, because you need iron to make the ferritin protein.”
— [23:05]

Clinical Pearl

[27:23]

Fatigue/alopecia/restless legs may require ferritin >75–100; “...give [such patients] iron, it stops falling out again. It didn’t work for me.”
— Dr. DeLoughery

4. Counseling Patients—Diet Myths & Realities

[28:17–32:26]

Heme iron (animal sources) is best absorbed; plant (non-heme) iron, e.g., from spinach, is poorly absorbed and can even chelate iron due to oxalates.
Eating steak isn’t enough for those already iron-deficient.

“If somebody’s iron deficient, just eating steak three times a day is not going to get them back up...they’re going to need supplementation.”
— [32:15]

5. Oral Iron Supplementation—Modern Best Practices

[33:27]

Once daily dosing (not TID)! Higher frequency increases hepcidin, blocking absorption.
With or without food? With food is fine for patient comfort and actual intake; “meaty” foods double iron absorption.
Vitamin C with iron helps (especially to counteract dietary inhibitors).
Avoid tea/coffee within an hour of iron—tannins drastically reduce absorption, not caffeine.
For adherence, daily or three-times-weekly (e.g., M/W/F) is fine.

“Once a day at most...People say take it on empty stomach - theoretically absorption may be better. People really don't like things on empty stomach.”
— [33:27]

“I’ve always wanted to actually make an iron pill wrapped in bacon...call it iron in a blanket.”
— [28:17]

Every Other Day Dosing Controversy

[37:09]

Every other day can improve absorption, but total iron repletion at 90 days is similar or slightly slower than daily dosing.
GI side effects less common with every other day; overall, patient preference/tolerance guides choice.

6. IV Iron—When and How

Indications:

Failure/intolerance to oral iron (no need to try endless oral formulations)
High pretest probability of non-absorption (bariatric surgery, IBD, ongoing bleeding, severe deficiency)
[48:10–49:19]

Dosing/Prep Selection:
[50:36–54:30]

Multi-dose iron salts (iron sucrose, ferrous gluconate): practical downfalls, adherence issues.
Preferred:
- Low Molecular Weight Iron Dextran: Single 1000mg dose, safe & well-tolerated.
- Ferumoxytol: 510mg x2 a week apart (off-label, single 1020mg dose works but not always insurance-covered).
- Ferric Derisomaltose: Fast, single dose, but more expensive.
Ferric Carboxymaltose: Watch for significant hypophosphatemia; avoid unless necessary.

“Single dose iron...One stop shopping, and boom, the patient’s repleted.”
— Dr. DeLoughery [51:28]

IV Iron Safety, Side Effects, and Counseling

[56:48–57:42]

Infusion reactions (not true allergy) occur 1–4% of the time and are minor; anaphylaxis is exceedingly rare.
No good evidence that IV iron increases infection in most settings.

“True, severe anaphylaxis, very, very rare – like 1 in 15,000. And so it’s a very safe product to give.”
— [57:11]

7. Population Pearls

Premenopausal women: Take a menstrual history—heavy periods underrecognized as a cause; GI workup unnecessary unless over 40 or with risk factors.

“You gotta take a menstrual history...that can really pay off.”
— [44:35]
Celiac workup: Always in men, and low threshold in women with unexplained anemia or GI symptoms.
Unexplained iron deficiency: 20–30% of cases, extensive workup remains “negative”—reassure, monitor, treat supportively.

8. Monitoring & Follow-Up

[58:41–60:46]

For oral iron: Check CBC at 2 weeks, expect 1g/dL rise in hemoglobin; monitor ferritin at 3 months, aiming >50 (or higher with ongoing symptoms).
For IV iron: Check ferritin at 4–6 weeks (earlier = artificially high). Repeat as needed; expect ferritins in 200–300s after repletion, not a toxicity sign.

Notable Quotes (/ Memorable Moments)

On public speaking:

“If you study, you actually know more than anybody else in the audience about it because it's fresh on your mind.”
— Dr. DeLoughery [05:53]
On heavy periods:

“Average American woman needs 2.4 to 3.54 mg of iron a day to keep up with menstrual losses...and average diet intake is 1.8 mg!”
— [44:35]
On iron-rich foods:

“Moose actually has the highest amount of iron in it.”
— [29:54]
On why spinach is not the answer:

“Spinach is a not that great a source of iron, and it hurts patients...it actually chelates iron.”
— [32:26]
On surprising ferritin cutoffs:

“Ferritin of 13 is not normal in any situation. Maybe for other forms of life, but not in humans.”
— [68:59]

Timestamps for Major Segments

[09:36] Initial anemia assessment, case intro, CBC review
[13:42] Systematic CBC reading, thalassemia/iron deficiency trick
[19:21] Iron studies: Ferritin vs. TIBC/Transferrin saturation
[21:04] Setting ferritin cutoffs & the pitfalls of population reference ranges
[27:23] Higher ferritin targets for restless legs/alopecia
[28:17] Dietary pearls & myths (heme vs. non-heme iron, spinach myth)
[33:27] Oral iron dosing, hepcidin, food/vitamin C/tea tips
[37:09] Once daily vs. every other day iron dosing controversy
[48:10] When to move to IV iron
[50:36] IV iron products—dosing, pros/cons, hypophosphatemia warning
[56:48] Safety of IV iron, reactions, counseling on side effects
[58:41] Monitoring response, CBC/ferritin follow-up
[68:59] Take-home points

Take Home Points (Dr. Tom DeLoughery) [68:59]

Iron deficiency is common—define it physiologically, not statistically. For ferritin, use 30 (minimum) or 50 (symptomatic) as your cutoff, not lab “normals”.
In women, take a menstrual history. It’s key and too often missed.
Prescribe iron once a day at most; give with food/meat for tolerance and absorption.
Don’t hesitate to move to IV iron—don’t “torture” patients with endless pill trials.
Ferritin in the 200–300s post IV iron is okay—don’t sweat it.
IV iron is safe—infusion reactions are rare and usually minor.

“Iron deficiency is really common… and we need to have a physiologic approach to lab values. 30, 50 ferritin cutoff, that’s what you got to keep in your mind. Ferritin of 13 is not normal in any situation… Iron once a day at most… and don’t be afraid to use IV iron.”
— Dr. DeLoughery [68:59]

For further learning, see Bethany Samuelson Bannow’s episode on high menstrual bleeding and Dr. Michael Auerbach on IV iron (referenced by the hosts).

Summary prepared for those seeking a comprehensive, practical update on iron deficiency anemia—and a few laughs.

#471 Iron Deficiency Anemia with Dr. Tom DeLoughery

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Summary

The Curbsiders Internal Medicine Podcast

Episode #471: Iron Deficiency Anemia with Dr. Tom DeLoughery

Episode Overview

Key Discussion Points & Insights

1. Approaching Anemia: Diagnostic Framework

Dr. DeLoughery’s Quick CBC Review

Parlor Trick: Distinguishing Thalassemia vs Iron Deficiency

2. Iron Studies: What Really Matters

3. Ferritin Cutoffs—A Paradigm Shift

Inflammation Pitfall

Clinical Pearl

4. Counseling Patients—Diet Myths & Realities

5. Oral Iron Supplementation—Modern Best Practices

Every Other Day Dosing Controversy

6. IV Iron—When and How

IV Iron Safety, Side Effects, and Counseling

7. Population Pearls

8. Monitoring & Follow-Up

Notable Quotes (/ Memorable Moments)

Timestamps for Major Segments

Take Home Points (Dr. Tom DeLoughery) [68:59]

For further learning, see Bethany Samuelson Bannow’s episode on high menstrual bleeding and Dr. Michael Auerbach on IV iron (referenced by the hosts).

Summary

The Curbsiders Internal Medicine Podcast

Episode #471: Iron Deficiency Anemia with Dr. Tom DeLoughery

Episode Overview

Key Discussion Points & Insights

1. Approaching Anemia: Diagnostic Framework

Dr. DeLoughery’s Quick CBC Review

Parlor Trick: Distinguishing Thalassemia vs Iron Deficiency

2. Iron Studies: What Really Matters

3. Ferritin Cutoffs—A Paradigm Shift

Inflammation Pitfall

Clinical Pearl

4. Counseling Patients—Diet Myths & Realities

5. Oral Iron Supplementation—Modern Best Practices

Every Other Day Dosing Controversy

6. IV Iron—When and How

IV Iron Safety, Side Effects, and Counseling

7. Population Pearls

8. Monitoring & Follow-Up

Notable Quotes (/ Memorable Moments)

Timestamps for Major Segments

Take Home Points (Dr. Tom DeLoughery) [68:59]

For further learning, see Bethany Samuelson Bannow’s episode on high menstrual bleeding and Dr. Michael Auerbach on IV iron (referenced by the hosts).